1. Field of the Invention
The present invention relates to a process for efficiently producing a compound having a carbonyl group and/or a carboxyl group (hereinafter referred to simply as "the carbonyl compound") useful as an important intermediate for physiologically active substances and amino acids from an inexpensive polyhydric alcohol.
2. Description of the Related Art
The carbonyl compounds including dihydroxyacetone (and its dimer), hydroxypyruvic acid, hydroxyacetone, pyruvic acid, glyceraldehyde (and its dimer), hydroxymalonic acid, glyceric acid, and lactic acid are very important intermediates for physiologically active substances and amino acids. As judged from the fundamental skeletons of these intermediates, it is conceivable that they may be derived from compounds having a secondary hydroxyl group, such as glycerol, 1,2-propylene glycol or derivatives of them.
Various processes have been proposed heretofore for deriving oxidized glycerol from glycerol by oxidation. For example, J. Org. Chem., 52, 2318 (1987) describes that glyceric acid is derived from glycerol by oxidation with nitric acid or mercury. However, this process is undesirable from the viewpoints of environmental pollution and waste water treatment. Further, although a process for producing glyceraldehyde by the electrolytic oxidation of glycerol is disclosed in British Patent No. 1051614, the concentration of the starting material, i.e., glycerol is too low for the practical application.
A process for producing dihydroxyacetone by oxidizing the secondary hydroxyl group of glycerol by an enzymatic reaction with Acetobacter sp. has been known. In addition, Japanese Patent Laid-Open No. 207255/1989 proposes a process for chemically synthesizing dihydroxyacetone by oxidizing glycerol with peracetic acid in an organic solvent. However, these microbial process and chemical synthesis process have problems in practice, since the yield is low and the concentration of the obtained dihydroxyacetone is low.
On the other hand, pyruvic acid is produced by the gas phase oxidation of lactic acid.
It is known that the oxidation products and dimers of them produced by the above-described conventional processes are thermally unstable and easily isomerized by a pH change. Therefore, these oxidation products or their dimers must be synthesized under mild conditions which are strictly controlled. However, the reactions conducted under the mild conditions have a defect that they take a long time. In the above-described conventional processes, the reaction must be conducted while the concentration is kept low in order to relax the inhibition of the reaction by the molecular association of the starting polyhydric alcohol and, in addition, these processes are unsatisfactory also from the viewpoint of the productivity.